Changing the Intention from Shortening to Completing the Prayer Behind an Imam Who Completes It
Machine translationRead the Arabic original
The questioner:
He says: Honorable Shaykh, may Allah grant you success. He says: I was traveling, and on the way I stopped to pray Maghrib and 'Isha' combined and shortened. When I wanted to pray 'Isha', I joined a congregation. I intended to shorten the prayer, but then I realized that the imam intended to complete it, so I changed my intention to completing it. He says: Is my action correct?
The Shaykh:
So, shortening the prayer while praying behind an imam who completes it is not permissible for you. You complete the prayer with the imam. Your ruling is the imam's ruling. There is hesitation on your part, so you do not intend to shorten the prayer except with an imam you know shortens it. As for an imam whose practice you do not know, you intend to complete the prayer. Yes.
The questioner:
And he asks, may Allah preserve you: If my action is not correct, do I have to repeat the prayer?
The Shaykh:
Without a doubt. Yes. Yes.
He says: Honorable Shaykh, may Allah grant you success. He says: I was traveling, and on the way I stopped to pray Maghrib and 'Isha' combined and shortened. When I wanted to pray 'Isha', I joined a congregation. I intended to shorten the prayer, but then I realized that the imam intended to complete it, so I changed my intention to completing it. He says: Is my action correct?
The Shaykh:
So, shortening the prayer while praying behind an imam who completes it is not permissible for you. You complete the prayer with the imam. Your ruling is the imam's ruling. There is hesitation on your part, so you do not intend to shorten the prayer except with an imam you know shortens it. As for an imam whose practice you do not know, you intend to complete the prayer. Yes.
The questioner:
And he asks, may Allah preserve you: If my action is not correct, do I have to repeat the prayer?
The Shaykh:
Without a doubt. Yes. Yes.
Source
شرح كتاب المنتقى من أخبار المصطفى صلى الله عليه وسلم، بداية من باب أول وقت العصر وآخره في الاختيار والضرورة — islamhouse.com (1:05:47)
The Arabic text is a machine transcription of the audio recording.